BIBLIOS

Document type
Academic documents

Document subtype
Master's dissertation

Title
Desenvolvimento de Metodologias de Medição de parâmetros Óticos de Fantomas de Meios Túrbidos Biológicos

Participants in the publication
Luís Miguel Marques Gonçalves (Author)
Pedro Manuel Cardoso Vieira (Co-Supervisor)
João Miguel Pinto Coelho (Supervisor)
Dep. Física
IBEB

Summary
The field of optics increasingly incorporates diagnostic techniques and less invasive and safer therapies in medicine, including the potential detection and treatment of cancer. The incidence of a laser beam on biological tissue allows, with a a particular focus, intensity and wavelength for the transfer of the necessary energy to induce apoptosis or other biochemical events. \nBiological tissue is a turbid material such that most of the incident photons are scattered, quickly reducing the intensity of a laser as it penetrates the tissue. The concentration of scatterers and absorbers determines optical coefficients and affects the efficacy of phototherapy techniques, which require an easy and safe method for their determination. \nIn this study, measurements were carried out using an integrating sphere with a series of diluted and gelled milk phantoms with agar to simulate human tissue. These measurements were subsequently used in an inverse algorithm applying the Inverse Adding Doubling (IAD) method, translating them into key optical properties: anisotropy, absorption coefficient, and the most complex to measure, the scattering coefficient. \nAn extensive methodology is presented for the measurements in the integrating sphere, considering the sensitivity and limitations of the technique, yet providing values that differ by an order of magnitude when compared to those found in the literature.


Institution
FACULDADE DE CIÊNCIAS E TECNOLOGIA DA UNIVERSIDADE NOVA DE LISBOA

Publication Identifiers

Keywords
Integrated sphere Absorption Scattering Inverse Adding Doubling Laser